{"record":{"author":{"account_ref":null,"orcid":null},"builds_on":[],"content_schema":"pubphys.content.revision/1","content_sha256":"395c6d9cd84ff1a9229d84e911648d03f10ab5e4d62557a5d3b9a0b566accff5","created":"2026-10-03T07:18:06Z","files":[],"origin":{"assisted_by":[],"kind":"seed"},"parents":["5475cf5dc5b1a72283d26dc95dc6e00d7ea4e00096a7c6492e409a1816eeb011"],"salt":"7f3a372be6ccacf01b3dcc08f2108c6d55ccfdcdf6fd54ce4cb4a48b1d4c4d94","schema":"pubphys.record/2","site":"pubphys.com","target":null,"type":"revision"},"content":{"answer_type":"value","assisted_by":[],"external_id":"med.focused-ultrasound.aberration-correction","kind":"well-posed","literature_status":"open","n":"1","parents":[],"plain":"The skull bends and absorbs sound unevenly, smearing the focus inside the head. Correcting for it currently needs an x-ray scan of the skull.","posed_since":"2000","precise":"Achieve transcranial focal placement accurate to 1 mm and pressure prediction accurate to 10 percent at 0.2 to 1 MHz without computed tomography of the skull, by inferring the skull acoustic properties (sound speed $2.4\\,\\mathrm{x}\\,10^{5} \\text{ to } 3.0\\,\\mathrm{x}\\,10^{5}\\,\\mathrm{cm}/\\mathrm{s}$, density, absorption, shear conversion) from ultrasound or magnetic resonance data. An answer is a method with verified focal position and amplitude in human skulls.","problem_ref":null,"references":"","settled_by":"Hydrophone measurement inside ex vivo human skulls, and in vivo displacement or thermometry confirmation, against the predicted focus.","status_note":"","title":"Transcranial focusing without a prior CT scan","topic_ref":"8f240ebd4ecd5f8e303bb3f92d02a60c846c51e2ff4c97cf08dac7930e62b3b4"},"attested":{"attestation":{"batch":null,"client_id":null,"id_token_sha256":null,"kind":"platform"},"record_hash":"93930a02d04d5619e085ab37e2d4461e7e9a9b32e772fe28426ea3df8025ebbd","schema":"pubphys.attested/1"},"envelope":{"attested_hash":"f4008dc25e58fe9f1f0b215e140472a327339760347eab94275efee9904eba80","platform_signature":{"key_id":"c6afc19b31429869751f06879c75cd64ea92654423d15b44be775bf1310a60da","sig":"yp4l7gdYwwYXcDLxy7GoDxZ6AOAoOxXJYC1WUxRtrMqT27IxcvoedDUU30ugV4y381ohAyi5snvx1_tc1jeuBQ"},"schema":"pubphys.envelope/1"},"record_hash":"93930a02d04d5619e085ab37e2d4461e7e9a9b32e772fe28426ea3df8025ebbd","leaf_index":1684}